B.Com

Both BMS and B.Com are graduation degrees, hence don’t go for BMS after completing B.Com. Instead, do MBA or any other PG course.

There are various certificate courses. If you want to do financial planning then CFP should be done. For financial market NISM certificate should be done.

You can learn Tally or work with a CA for experience.

Not necessarily BA in economics required. Graduate from any disciplines with 50% or more may apply for MA in economics.

Most of the college accept admission on the basis of class 12th score only, though if you manage to score something above 90% in 12th. There are good chances to get admission in Delhi University.

Hi,
You may pursue for CIA course from ICA. After course completion they provide "anytime job card".

Based on B.Com, I am of the opinion that IT MBA IT will be an ideal higher qualification for you. If you can do some courses to gain BFSI domain knowledge and get IIBA certification to become a qualified BA, any IT company will hire you. With MBA IT you will be qualified for pre-sales support, Sales

No, mathematics is not compulsory to pursue B.Com, but you need to have good knowledge of mathematics, which can help you in calculations.

You can pursue professional courses like:-
Chartered Accountancy
Company Secretaries
Accounting Technician Course
Or you can choose Academic Studies like:-
M.Com
MBA
Also you can start preparing for Govt. Competitive Exams
All the best